Thursday, September 6, 2012

The Last Hummingbird of Fall

This Ruby-throated Hummingbird photographed at my feeder last September is probably a first-year male, based on his "five o'clock shadow."

Every September, I get inundated with questions
about when we should take down hummingbird feeders. The vast majority of
Ruby-throated Hummingbirds light out for the territory in August, and most of
us in northern states notice our last ones on or before Labor Day. If you’re
putting out hummingbird feeders for your own enjoyment of these tiny dynamos,
take in your feeders when you stop seeing them. But unless you’re watching your
feeder every minute of every daylight hour, you are almost certainly getting
occasional visits from hummingbirds migrating through. Keeping feeders
available can give these last ones, mostly young of the year, a quick supply of
calories. A hummingbird feeder provides far more carbs per visit than individual
flowers do, so a feeder allows migrants to spend more time traveling and less searching
for food.

If you keep feeders up in fall, keep the sugar water fresh. It’s
easy to forget to change the water every few days, but essential if you want to
do more good than harm. Even before sugar water gets cloudy, it’s fermenting,
which can cause liver damage. Fermentation goes faster in warmer temperatures,
so we can change the water less frequently during cool fall weather than in
summer heat, but need to keep the task on our radar.

In spring and summer, several feeders can accommodate these
aggressively territorial birds with a minimum of squabbles. Because so few
hummingbirds are present this late, it is less expensive and far easier to maintain
just one or two feeders. It’s also wise to set fall feeders in the windows you
spend the most time near.

The likelihood of seeing any hummingbird in late fall is small, but
you have a reasonable chance of seeing a real rarity. I’m only aware of four or
five hummingbirds visiting my feeders over the years after September 15, but
one of them was a rare visitor from the West who turned up on November 16, 2004
and remained until December 3. Her identity was under some dispute—she was most
likely a Rufous Hummingbird, but without collecting a feather for DNA it was
impossible to be certain. If a qualified hummingbird bander had been available
to trap her in a standard hummingbird trap, I’d have been fine with taking
measurements and macro photographs of her.

Unfortunately, the only banders available
used mist nets, which are very stressful and dangerous for hummingbirds even
when the banders specialize in handling them. To verify her species, they
wanted to remove one tail feather, but birds immediately shunt resources to
replacing plucked feathers, and that time of year when a minimum of protein was
available, I just couldn’t justify putting her through any of that. So although
I have plenty of photos of her and think of her as a Rufous Hummingbird, she’s
listed as “Selasphorus sp.” in the Minnesota
Ornithologists’ Union record books.

Rufous hummingbird in northern Wisconsin in August, 2007

Wisconsin and Minnesota have both had amazing visits by
out-of-range hummingbirds in fall, including such shocking species as a Green
Violetear visiting a La Crosse feeder one October, an Anna’s Hummingbird in Grand
Marais one November, and a Calliope Hummingbird in the Twin Cities one December.

Feeders did not lure these birds out of their normal ranges. It’s impossible to
know how many out-of-range hummingbirds just quietly die with no one to notice.
When my backyard Rufous Hummingbird took off at mid-morning on December 3rd,
I was petrified that she wouldn’t encounter another friendly feeding station no
matter what direction she took. Ever since she showed up, I’ve tried to keep at
least one feeder available and fresh throughout October and November. Even if I
never look at the window, and never know if any hummingbirds came, I feel good
knowing if one does pass through, it won’t leave my yard hungry.

3 comments
:

Love the thoughts behind the feeder. I think about this migration and how dangerous a path it is that they have to take to return to these places. Right now most of them are heading down through Arizona. It certainly gets busy here in our city, canyons and mountain tops.

Its great to see information about what to do with hummingbird feeders during migration. My thoughts are to leave the feeders out until temperatures are in the freezing range. This way any hummingbirds coming through will be able to fill up before their long journey. Nature will guide them to when its time for them to migrate.

I'm fortunate that I still have hummingbirds around; in fact, only this week I saw my first immature male rufous hummingbird (we'd get no others here in Utah) at the feeders. He wasn't quite as aggressive as his paternal relatives were a few weeks ago, but it was a delight to see him!